DTC P0130 A/F/O2 Sensor Circuit Bank 1 Sensor 1: Notes

DTC detecting condition:

Immediately at fault recognition

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Fig 1: A/F/O2 Sensor Circuit Bank 1 Sensor 1 - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

CHECK FRONT OXYGEN (A/F) SENSOR DATA.
1. Start the engine and warm up engine until coolant temperature is higher than 75°C (167°F).
2. Idle the engine for one minute or more.
3. Read the value of A/F Sensor output lambda 1 using the Subaru Select Monitor or a general scan tool.
  NOTE:
  - Subaru Select Monitor
    For detailed procedures, refer to "Data Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Subaru Select Monitor .
  - General scan tool
    For detailed operation procedures, refer to the general scan tool operation manual.
Is the value of A/F sensor output lambda 1 1.20 - 3.00 V?
- Yes : Go to 2.
- No : Go to 3.
CHECK FRONT OXYGEN (A/F) SENSOR DATA.
1. Race the engine so that the engine speed stays at 3, 000 RPM. (Five times in total)
2. Read the value of A/F Sensor output lambda 1 at racing using the Subaru Select Monitor or a general scan tool.
  NOTE:
  - Slowly depress the accelerator pedal to increase engine speed up to 3, 000 RPM, keep it for approximately 5 seconds, and quickly release the accelerator pedal to decrease engine speed.
  - Normally, the air fuel ratio is rich during racing.
Is the value of A/F sensor output lambda 1 2.5 V or more?
- Yes : Go to 5.
- No : Go to 3.
CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connectors from front oxygen (A/F) sensor.
3. Disconnect the connector from ECM.
4. Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector.
  Connector & terminal
  
  (E158) No. 15 - (E24) No. 1:
  
  (E158) No. 27 - (E24) No. 4:
  
  (E158) No. 39 - (E24) No. 5:
Is the resistance less than 1 Ω?
- Yes : Go to 4.
- No : Repair the open circuit of harness between ECM and front oxygen (A/F) sensor connector.
CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.
Measure the resistance between ECM and engine ground.

Connector & terminal

(E158) No. 15 - Engine ground:

(E158) No. 27 - Engine ground:

(E158) No. 39 - Engine ground:

Is the resistance 1 MΩ or more?
- Yes : Go to 5.
- No : Repair the ground short circuit of harness between ECM and front oxygen (A/F) sensor connector.
CHECK EXHAUST SYSTEM.
Check exhaust system parts.
NOTE:
Check the following items.
- Looseness and improper fitting of exhaust system parts
- Damage (crack, hole etc.) of parts
- Looseness of front oxygen (A/F) sensor
- Loose part and improper installation between front oxygen (A/F) sensor and rear oxygen sensor
Is there any fault in exhaust system?
- Yes : Repair or replace faulty parts.
- No : Replace the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Front Oxygen (A/F) Sensor .